ArticlePDF Available

Iconography in Bradshaw rock art: Breaking the circularity


Abstract and Figures

Background: Interpreting the symbols found in the rock art of an extinct culture is hampered by the fact that such symbols are culturally determined. How does one break the circularity inherent in the fact that the knowledge of both the symbols and the culture comes from the same source? In this study, the circularity is broken for the Bradshaw rock art of the Kimberley by seeking anchors from outside the culture. Methods: Bradshaw rock art in the Kimberley region of Australia and Sandawe rock art in the Kolo region of Eastern Tanzania were surveyed in six visits on foot, by vehicle, by helicopter and from published or shared images, as well as from the published and online images of Khoisan rock art. Results: Uniquely shared images between Bradshaw and Sandawe art, such as the ‘mushroom head’ symbol of psilocybin use, link the two cultures and indicate that they were shamanistic. Therefore, many mysterious features in the art can be understood in terms of trance visualisations. A number of other features uniquely link Bradshaw and Sandawe cultures, such as a special affinity for small mammals. There are also many references to baobabs in early Bradshaw art but not later. This can be explained in the context of the Toba super-volcano, the likely human transport of baobabs to the Kimberley and the extraordinary utility of the baobab. Conclusion: Many more mysterious symbols in Bradshaw rock art might await interpretation using the approaches adopted here.
Content may be subject to copyright.
cxo_648 403..417
Iconography in Bradshawbrock art: breaking the circularity
Clin Exp Optom 2011; 94: 5: 403–417 DOI:10.1111/j.1444-0938.2011.00648.x
Jack Pettigrew FRS
School of Biomedical Sciences and
Queensland Brain Institute, University of
Queensland, Brisbane, Australia
Background: Interpreting the symbols found in the rock art of an extinct culture is
hampered by the fact that such symbols are culturally determined. How does one break
the circularity inherent in the fact that the knowledge of both the symbols and the culture
comes from the same source? In this study, the circularity is broken for the Bradshaw rock
art of the Kimberley by seeking anchors from outside the culture.
Methods: Bradshaw rock art in the Kimberley region of Australia and Sandawe rock art
in the Kolo region of Eastern Tanzania were surveyed in six visits on foot, by vehicle, by
helicopter and from published or shared images, as well as from the published and
online images of Khoisan rock art.
Results: Uniquely shared images between Bradshaw and Sandawe art, such as the ‘mush-
room head’ symbol of psilocybin use, link the two cultures and indicate that they were
shamanistic. Therefore, many mysterious features in the art can be understood in terms
of trance visualisations. A number of other features uniquely link Bradshaw and Sandawe
cultures, such as a special affinity for small mammals. There are also many references to
baobabs in early Bradshaw art but not later. This can be explained in the context of the
Toba super-volcano, the likely human transport of baobabs to the Kimberley and the
extraordinary utility of the baobab.
Conclusion: Many more mysterious symbols in Bradshaw rock art might await interpre-
tation using the approaches adopted here.
Submitted: 12 May 2011
Revised: 6 June 2011
Accepted for publication: 10 June 2011
Key words: baobab, Bradshaw rock art, mushroom head, Sandawe, Toba megavolcano, trance visualisations
a. This paper is based on a presentation at the
Southern Regional Conference of Optometrists
Association Australia in Melbourne, 16 May
2011, at which the author was presented with
the H Barry Collin Research Medal. In the origi-
nal presentation there were several examples of
more physical research in vision, as befits study
by an optometrist, that were used as a prelude
to the substance of this paper, in which more
abstract visual inferences are needed to inter-
pret ancient rock art.
b. There are several alternative, indigenous
names for this art, such as Gwion Gwion, Jingo
Jinga, Going Going et cetera). At first sight,
these might be considered preferable to the
non-indigenous, although internationally well
established, ‘Bradshaw’ but there are several
reasons for continuing to use the latter. The key
reason for avoiding the recently proposed
terms is that they have the implication of conti-
nuity between Bradshaw and indigenous cul-
tures, an open question for which Walsh was
attacked, but one requiring much more
research at present, despite the fact that conti-
nuity is commonly assumed. The key issue in
this discussion is preservation of cultural heri-
tage but it is often forgotten that this cuts both
ways, to apply both to the extinct Bradshaw
culture as well as to indigenous Aboriginal
culture, whether or not there might have been
a discontinuity between them. There are plenty
of voices speaking up on behalf of indigenous
Kimberley cultures. If the extinct Bradshaw
culture was discontinuous, who will reveal this
and speak up on its behalf, using science to
make the reconstruction, instead of assuming a
continuous scenario and so running the risk of
losing many of the important details of the
minority culture as it is submerged?
© 2011 The Author Clinical and Experimental Optometry 94.5 September 2011
Clinical and Experimental Optometry © 2011 Optometrists Association Australia 403
Bradshaw rock art is narrowly confined to
Kimberley sandstone in North West (NW)
Australia1. The first Western description,
with a remarkably accurate drawing of a
large mural, was by the Melbourne land-
owner, Joseph Bradshaw, who was search-
ing for his pastoral lease in the Kimberley
in 1891 and after whom this rock art is
internationally known. It is thought that
there are around 100,000 Bradshaw art
sites, all confined to the Kimberley and
the subject of much study and debate. The
age and originators of the art are obscure
but a Pleistocene origin is very likely,
based on three independent measures
that include thermoluminescence studies
of wasp nests overlying the art (17,000
to 30,000 years),2,3 depicted megafauna,
which have been extinct for 46,500 years4,5
and the age of boabs that appear to have
been brought from Africa to Australia by
this culture (less than 100,000 years).6
The much more recent Holocene age
given by radiocarbon studies of the art
(3,000 years)7is completely out of line
with the three others, probably because
the paint of Bradshaw art has been
replaced by a living layer of fungi and bac-
teria, the continuous replenishment of
which would not show the expected
decline of radiocarbon levels that nor-
mally occurs at death.8That the biofilm
occupies the exact boundaries of the art
also helps to explain how Bradshaw paint-
ings, exposed to the weather, could look
so recent despite great age, if contours are
kept fresh by continuous in situ replace-
ment of the pigmented microorganisms.
The greatest exponent of Bradshaw art
was the late Grahame Walsh, who amassed
over one million images of the art during
30 years of visits to the rugged Kimberley
and recorded them in extraordinary
books.1,9 I never met him, despite the
inspiration that he has provided for this
work, but my expertise in unusual human
brains10 has allowed me to identify him as
a savant with extraordinary visual powers
of attention and memory that had presum-
ably resulted, as with many other savants,
from the two brain injuries he sustained
early and later in life.
In an appalling display of academic bul-
lying, Australian anthropologists used a
widely circulated open letter to attack this
autodidact, who knew orders of magni-
tude more than they did collectively about
the subject in hand (based on a facsimile
of the letter from five authors on page 440
of Walsh1). The main bone of contention
was Walsh’s heretical suggestion that there
might have been more than one early wave
of human migration to the Australian con-
tinent,9but the assailants were also critical
of his suggestion that there might be
underlying meaning in the abundant
symbols of Bradshaw art. In contrast to the
first disagreement, where Walsh’s superior
knowledge probably put him on the right
track—only more science can tell—the
second disagreement was not on such
solid ground for Walsh because of a diffi-
cult circularity. The problem with Walsh’s
thesis of iconography in Bradshaw art is
that icons are culturally determined and
cannot be understood in isolation from
their culture, yet all we have as evidence of
the extinct Bradshaw culture is the rock
art, the icons of which we are trying to
understand. Therefore, progress requires
that this circularity be broken in some way.
In the present study, evidence is sought
from outside the Bradshaw culture in an
effort to constrain interpretation of its
icons by means of external references,
such as the study of another, extant
culture with overlapping iconography, the
exponents of which can therefore act as
witnesses to the symbols that can be found
in their rock art. This is found to be true
for the Sandawe culture, one of the three
surviving click-language speaking rem-
nants of the San peoples who were once
widespread in Africa and now occupy iso-
lated areas in the South (Khoisan), North
West Tanzania (Hadza) and East Tanzania
(Sandawe). The Sandawe use some icons
that are also found unmistakably in Brad-
shaw art but are not known for other
African rock art in the Khoisan tradition.
Exact parallels between the icons of Brad-
shaw and Sandawe rock art show that the
two cultures shared many shamanist fea-
tures, of which the use of hallucinogenic
mushrooms is a key. An identical, specific
icon in both cultures is interpreted by
living Sandawe as indicating use of hallu-
cinogenic mushrooms. The discovery of
the chemical means for a trance then
establishes, inter alia, that trance visualisa-
tion is an important component of the
rock art in both cultures. Using this spe-
cific icon as a foundation that requires no
circular inference from within Bradshaw
art, one can interpret a wider range of
Bradshaw symbols in the light of Lewis-
Williams’ thesis11 about the diverse forms
of trance visualisations experienced and
depicted by shamans.
‘Mushroom head’ depiction is
shared by both Sandawe and
Bradshaw rock art
The use of trance is widespread among all
the branches of the San (such as Khoisan,
Hadzabe and Sandawe, as well as the
Saharan tribes responsible for similar rock
art that were also likely to have been San)
and this was probably true when the San
were more widespread over Africa and the
Bradshaw culture was alive. Chemical
inducement of trance with ‘magic’ mush-
rooms (Psilocybe spp.) seems to have been
confined to the Sandawe in Africa (and
perhaps also to Saharan tribes, who
have specifically depicted the mushroom
itself).12 Psilocybe mushrooms might have
been used as a rapid technique of trance
induction to help shield the older, more
frail shamans from the physical rigours of
the usual method of inducement involving
many hours or days of chanting and
stamping. The ‘mushroom head’ depic-
tion is striking and unmistakeable and is
found in both the Bradshaw and Sandawe
(from the Kolo panels, near Kondo in
Tanzania) rock art12 but not in the
Khoisan or Hadzabe rock art. Sandawe
shaman witnesses testify that this depiction
(Figure 1) represents the feeling that one
can experience while in a psilocybin-
induced trance.13 Since the icon is identi-
cal in both Sandawe culture and the
extinct Bradshaw culture, we can infer that
psilocybin-induced trances were a feature
of both cultures and that trance might be
evident in the rock art. In fact, ‘mushroom
Iconography in Bradshaw rock art Pettigrew
Clinical and Experimental Optometry 94.5 September 2011 © 2011 The Author
404 Clinical and Experimental Optometry © 2011 Optometrists Association Australia
head’ depictions are not uncommon in
Bradshaw art, while associated trance visu-
alisations are even more widespread, as
described below.
Confirmation of the inference about
‘mushroom head’ comes from depictions
of ‘mojo bags’ in Bradshaw art. These are
small drawstring bags on a short leash,
which means they can be worn from the
shoulder but are hidden in the armpit. In
the Sandawe culture they contain the sha-
mans’ repository of hallucinogenic herbs
and mushrooms. Mojo bags are quite
common in Bradshaw depictions where
they are unmistakeable in axillary position
and size when compared with a larger,
lower ‘dilly bag’ on the same figures
(Figure 2). Shared icons in Bradshaw and
Sandawe rock art are consonant with
other less-specific shared features of the
two cultures, such as a special relation
with small mammals (well documented
in Sandawe lore and evident as small
marsupials on Bradshaw headdresses), use
of nets for hunting, and close-cropped
curly hair observed on Bradshaw figures
in rare cases (L Scott-Virtue, personal
Pervasive influence of trance
visualisations in Bradshaw
On the basis of the evidence of ‘mush-
room head’ and ‘mojo bag’, if one accepts
the possibility that the Bradshaw culture
was shamanistic and used hallucinogenic
trance visualisations in its depictions,
many of these latter can now be
David Lewis-Williams11 made a major
contribution to this line of study, concen-
trating on Khoisan rock art, and set out
the following general topics that cover
most images from hallucinogenic trance.
Since the first listed depictions of geo-
metrical patterns are derived from entopic
experiences that are common to all
human brains and can be elicited by a
variety of means, it is not surprising to find
them in a variety of cultures. Their pres-
ence nevertheless indicates a culture that
was familiar with the practice of trance
visualisation. The other examples can
have a cultural overlay, which can be
revealing or obscuring of the culture
like the eland transformation famously
explained by Lewis-Williams11 and the
baobab transformations described for
the first time here. These depend on the
external constraints, as argued here for
‘mushroom head’, which seems to have
been restricted in its distribution to link
Figure 1. ‘Mushroom head’ depiction shared by Sandawe (A) and Bradshaw (B) cultures.
Extant Sandawe shamans testify that this depiction represents the subjective experience
of a trance under the influence of magic mushrooms (Psilocybe spp.). We can validly
assume that these identical icons have the same meaning in the Bradshaw culture, even
though it is extinct, without extant human witnesses.
Figure 2. Tassel Bradshaw figures from the Kimberley East Coast, showing two kinds of
drawstring bags, (A) a smaller one in an axillary location that may aid its concealment and
security (‘mojo bag’), and (B) a larger, lower, hand-held bag of more conventional size
and location (‘dilly bag’). An axillary pouch like this, also called a mojo bag in parts of
Africa, is used by Sandawe shamans to carry Psilocybe mushrooms and other herbal
paraphernalia in the same way that the axillary bag is used in these Bradshaw depictions.
Also illustrated here is an example of the common occurrence of a small mammal in close
apposition to a human figure (C). The long, pointed ears and paler tail are diagnostic of
the extinct, lesser bilby, Macrotis leucura,(D).
Iconography in Bradshaw rock art Pettigrew
© 2011 The Author Clinical and Experimental Optometry 94.5 September 2011
Clinical and Experimental Optometry © 2011 Optometrists Association Australia 405
Sandawe and Bradshaw cultures more
strongly than other trance visualisations.
There are numerous depictions based
on trance visualisations, namely:
1. seeing bright geometric patterns (grids
of dots, spirals, concentrics)
2. floating or flying (‘astral travel’)
3. transformations, from one thing into
another (for example, body part to
tree, dendrianthropes, hind limb
4. transformations into animal forms
5. micropsia/macropsia (‘little people’;
6. polyopsia (repeated objects in a line)
7. passage through a tunnel
8. ability to see mercurially, although
vividly (altered perception of time).
Examples of most of these trance phe-
nomena can be found among Bradshaw
depictions, with the exception of clear
examples of tunnel passage, complete
darkness and altered time perception, all
of which are difficult to depict. The last
might be replaced by an alternative
symbol that we cannot decipher at
Some of these trance visualisations are
Geometrical patterns are not unusual in
Bradshaw art. Some bear a striking resem-
blance to similar patterns in Sandawe rock
art, such as the concentric-headed figures
shown in Figure 3, which are also called
‘onion skin’ figures.
Hallucinogen-induced sense of travel is a
striking feature of the trance experience
that attracts recreational use, particularly
for the out-of-body (astral) component
that usually accompanies it. The many
examples of horizontally positioned
figures in Bradshaw art are likely to repre-
sent this visualisation. A large number of
such flying/swimming figures are also
found together in the famous Saharan,
‘Cave of Swimmers’, rock art discovered at
Gelf Kebir by Almasy14 and popularised
in Ondaatje’s novel, The English Patient.
Almasy thought that the figures repre-
sented actual swimming but this is unlikely
to be the case for the horizontal Bradshaw
figures, which are inappropriately dressed
for swimming, with complex costumes,
several accoutrements, large headdresses
and elaborate hairstyles. The Saharan rock
art figures are unclothed, so it is not so
easy to reject a true swimming role for
them on the basis of an attire that is too
complex, as we have done for the horizon-
tal Bradshaw figures, but they do have very
unusual postures, such as legs bent at the
knees, that seem more fitting to trance
visualisations than to real swimming.
The ‘grid of dots’ depiction is also
common in Bradshaw art and two
examples (Figures 4 and 5) are shown
to the left of human figures that also
show signs of trance visualisation, such
as therianthropes (kangaroos) and micro-
psial figures. There is a strong associa-
tion between such a grid and death
in some cultures (A Weiler, personal
One of the most compelling effects of a
hallucinogen is the blurring of object
boundaries that takes place, so that, for
example, one’s hand lying on the table
becomes continuous with the table. The
expansive feeling that results can lead to
the perception of a connection to the
cosmos and God, hence the modern, pref-
erable term for these chemicals, namely,
‘entheogen’ (evoking God).14 One conse-
quence of this expansion of consciousness
is that transformation visualisations are
possible, with hybrid depictions between
animals and humans (therianthropes) and
between trees and humans (dendrian-
thropes). In some cases, it might be
difficult to distinguish between such trans-
formations and mere dress decoration but
kangaroo heads with long arms leave no
other interpretation (Figure 4), as does the
transformation of a human limb into a
baobab branch illustrated later. This latter
Figure 3. Concentric (‘onion skin’) depiction of head, in figures from both Sandawe (A)
and Bradshaw (B) rock art are examples of geometric trance visualisation.
Iconography in Bradshaw rock art Pettigrew
Clinical and Experimental Optometry 94.5 September 2011 © 2011 The Author
406 Clinical and Experimental Optometry © 2011 Optometrists Association Australia
depiction is a striking transformation that
has not, as far as is known, been put forward
before and has an important implication
for the thesis that baobabs played a saviour
role for ancestors (detailed below). Lewis-
Williams’ insight11 that transformation
plays such an important role in Khoisan
rock art removed many of its most mys-
terious elements, like the depiction of a
human figure with hooves on its legs lying
next to an eland. No doubt it will aid
further interpretation of Bradshaw art,
now that we know that trance visualisation
and transformation play a role there too.
‘Little people’ alongside larger human
figures have always been a talking point of
discussions about Bradshaw art (Figure 6).
While a minority of observers attribute
giantism to the larger figure (for example,
Bednarik15), the more usual attribution is
the reverse, with the tiny, more simply
drawn, more dynamic figures thought to
be the miniature versions, while the
figures with the usual apparel and ac-
coutrements considered to be normal,
unmodified size. The polarity matters little
in this context, because both micropsia
and macropsia can occur on different
occasions in a hallucinogenic trance. A
second set of figures with a dramatically
different size usually occurs alongside
other hallmarks of trance visualisation,
such as therianthropes and geometrical
patterns (Figures 3 and 4).
Those with a penchant for the improb-
able might propose the alternative
explanation that ‘mushroom head’ has
appeared independently in two widely
separated cultures. Apart from the striking
similarity between the icons, there are
several reasons that argue against their
convergent evolution in this way. The icon
seems to be unique to the Sandawe among
all the other San tribes in Western Tanza-
nia (Hadzabe) and Southern Africa
(Khoisan) that also practise various forms
of shamanistic trance visualisation. There
is no evidence that these related groups
have discovered the use of psilocybin or
have used the ‘mushroom head’ icon.
Instead, they used prolonged chanting
and stamping to attain the trance state,
Figure 4. Figure in the horizontal ‘swimming-floating’ posture that may represent travel
in a trance rather than real swimming because of the inappropriateness for swimming of
elaborate dress, accoutrements and headdress (A). The hairstyle is also elaborate (B) and
may originally have represented decoration with coloured beads by ochre that has now
faded to leave the dotted appearance. It is usual to find further exemplars of trance
visualisation in a panel, once the first is found. In this case there is the bodily distortion
of the feet and legs (‘hindlimb attenuation’) (C), micropsia (‘little people’ running) (D)
and the geometric grid of black dots (E). Note the difference between the hallucinogenic
dots (E) and the linear arrangement of dots that follow the contours of what was probably
an outline of coloured ochre in the hair (B). The latter (B) can be mistaken for the
former (E), with an invalid rejection of the Lewis-Williams thesis.
Figure 5. Further examples of trance visualisations in a cluster: (A) the entopic phenom-
enon of a geometrical grid of dots; (B) therianthropes (half human/half kangaroo); (C)
micropsia (a dwarfed figure with headdress and batons).
Iconography in Bradshaw rock art Pettigrew
© 2011 The Author Clinical and Experimental Optometry 94.5 September 2011
Clinical and Experimental Optometry © 2011 Optometrists Association Australia 407
the features of which are shared between
mania and chemical hallucination be-
cause they all share the same fundamental
human neural apparatus. Therefore, par-
allel, separate evolution of psilocybin use
with the same icon in rock art in Australia,
far from Africa, seems less likely than a
direct link between the Sandawe and Brad-
shaw cultures.
This seems to be reinforced by a
number of other parallels between the two
cultures. Sandawe have the unusual ‘pep-
percorn curls’ and small stature that char-
acterise the San groups and this also seems
to apply to the Bradshaw people, as can be
deduced on those rare occasions when
hair is depicted in Bradshaw art and from
the use of familiar objects such as scales to
estimate stature from paintings. These
estimates, using the size of the boab pod
and the lesser bilby as a scale, give a short
stature of around five feet for the human
models used for human figures that were
unambiguously paired with one of the
scales in Bradshaw art. Estimates from San
and Sandawe art using the shoulder
height of adjacent cattle also give values
around five feet, in contrast to measure-
ments of Bantus and Australian Aborigi-
nes’ height, which are closer to six feet.16
Sandawe also had an unusual feature of
their folk tales that involved identifying
with small mammals, the characters of
which are believed to have imbued the
Sandawe with great resourcefulness and
cunning. These character traits stand in
contrast to traits imbued from the African
fauna by other tribes, such as the Masai
character of pride that can be linked to
lions. Small animal traits of deviousness
and resourcefulness seem to have given
considerable difficulty to German con-
querors of the Sandawe.17 We do not have
any direct evidence of the folk tales of the
Bradshaw culture but a striking feature of
their depictions, so far unexplained, is the
frequent depiction of small marsupials in
direct association with human figures,
either suspended ritually in the air nearby
or walking on the headdress of a human
figure (for example, Figure 2). This is con-
trary to Bednarik who has apparently seen
these depictions, many of them in the
public record.15 These depictions of small
mammals can often be identified with the
lesser bilby, Macrotis leucura, which is
extinct, but the measurements and fea-
tures of which are nevertheless well
known, namely, long pointed ears and
uniform pale tail in contrast to the black–
white partition of the greater bilby’s tail.
The striking and unusual predeliction for
small mammals in both cultures seems
unlikely to be a coincidence. Sandawe also
worshipped the praying mantis, for which
there is a whole class of less-than-veridical
depictions in Bradshaw art, also otherwise
unexplained, but possibly another
common feature to add to the growing list
of parallels between the cultures.
Awkward corollary
Accepting a direct connection between
the two cultures has an apparently
awkward corollary, namely, that they had
somehow bridged the gap between them
Figure 6. Micropsia in a figure with a loop (of unknown significance), adjacent to a
partially-obscured larger figure with boomerangs and waist pouch. Note that some
observers reverse this size polarity, attributing abnormal larger size (giantism) to the
larger figure (macropsia). Both perceptual directions are possible in trance, so this
difference of opinion is of little consequence here. The simplified outline and dress of
the small figure is more in keeping with micropsia, since accoutrements on the larger
figure are like those on normal figures in panels, where there is no micropsia/macropsia.
Iconography in Bradshaw rock art Pettigrew
Clinical and Experimental Optometry 94.5 September 2011 © 2011 The Author
408 Clinical and Experimental Optometry © 2011 Optometrists Association Australia
across the Indian Ocean. Apart from the
obvious geographic fact that the Sandawe
would have had ready access to their east
coast and thereby to an Indian Ocean
pathway to Australia, there does not seem
to be any suggestion, at first sight, that this
might have been possible. There is pres-
ently no evidence that the Sandawe had
seafaring expertise, although the very long
history of sea faring from the nearby port
of Kilwa in Eastern Tanzania hints that a
co-operative venture so long ago might
have been possible between Sandawe and
coastal tribes, given that the Sandawe
might have had enough baobab seed to
trade with starving tribes that lacked
access to these trees. Against the lack of
evidence of boat use by the Sandawe,
there are depictions in Bradshaw art of
large seafaring boats, probably of fibre
construction based upon the horizontal
striations in the depicted hull. A boat in
one such depiction had a three-metre
prow and 29 passengers and crew (M
Myers, personal communication).
An ancient African–Australian
Many commentators have considered it
ludicrous to suggest that a Palaeolithic
culture, without navigational skills or geo-
graphic knowledge of other continents,
could have found their way by sea to Aus-
tralia from Africa. This is understandable
speculation in the negative sense but it
tends to be countered by irrefutable facts
that point in the opposite direction. As in
any great mystery to solve, we need moti-
vation, means and opportunity.
The Toba event, the largest mega-
eruption in the previous two million
years, occurred around 74,000 years ago
in Sumatra. Its ash cloud and sulphate
cloud had devastating consequences for
humans, which are described in more
detail below. The timing of this super-
volcano eruption was appropriate for
these early human migrations and its mag-
nitude meant that the sun was completely
blocked by the sulphate cloud for a
numbers of years, impacting savagely on
hunter gatherers.
The depictions of boats in Bradshaw rock
art suggest that they were large, ocean
going and constructed of bundles of reeds
(Figure 7).
In February, opportunity arises when the
prevailing Indian Ocean easterlies reverse
direction to give way to vigorous westerlies
that are capable of driving even sluggish
raft-like reed boats to the Kimberley in
feasible time,18 with judicious paddling
and canoe sails (no depicted boats have
masts, but one cannot rule out small, per-
sonal canoe sails, which are still used by
islanders in the north east Indian Ocean).
Because the present thesis concerns the
shamanistic rituals of both the Sandawe
and Bradshaw peoples, it is highly likely
that shamans would have been urged to
deal with the catastrophic darkness post-
Toba. For San people like the Sandawe,
who had great sensitivity and knowledge of
the sun, moon and stars, years of darkness
would have had a devastating impact on
their psyche, putting aside the horrors of
the famine. Magical practice, ‘to bring the
sun back’, would no doubt have taken
advantage of the Sandawe’s known profi-
ciency with the heavens and perhaps have
led to a seafaring expedition in a sunrise
direction towards the known usual source
of the sun, and therefore coincidentally to
NW Australia.
In the month of February, the sun is still
around eight degrees south of the equator
in the southern hemisphere, so a bearing
for sunrise from the Tanzanian coast,
from a latitude of say, 9 degrees south,
would head unknowing voyagers directly
to the Kimberley in NW Australia (at 17
degrees south).
Food would not have been a problem
no matter how long the voyage turned out
to be, because the Sandawe lived in the
heart of one of the most abundant baobab
forests on the continent at that time,
before the evolution of the modern
coastal species. The convenient natural
packaging of baobab pods is very long
lasting (years if stored away from the
damp) and provides seeds that are sustain-
ing for an adult at 300 gram per day (half
a pod). Fresh water would have been more
of a problem for many reasons. It would be
difficult to predict in advance how much
to take. Storage on board would probably
be a problem in a Palaeolithic culture
without suitable large containers. Finally,
the weight of water might seriously burden
the boat (one would need roughly one’s
own weight in water for every fortnight of
travel under present conditions on the
equator, although this would have been
less in the overcast, cool, ice-age condi-
tions that probably prevailed post-Toba).
Fortunately, the voyagers might not have
needed to carry much fresh water because
rain was plentiful in the ice age conditions
that prevailed 70,000 years ago. This
seems perverse, because it is well known
that the continents were drier during the
ice age but apparently there was some sort
of global equilibrium so that reduced con-
tinental rainfall was balanced by increased
rainfall over the oceans, particularly over
the more eastern Indian Ocean, which
would have made up the latter part of such
a voyage.
It might be argued that the Pilot Chart-
derived18 equatorial westerlies, making a
west-east voyage more favourable, are not
indisputable facts, because they apply to
present-day weather conditions and not to
those that prevailed during the last glacial
age when the proposed voyage would have
taken place. This is a valid objection,
because both simulations and indirect
measures of temperature and other cli-
matic conditions show how different the
last glacial age was, with mean equatorial
temperatures up to 10°C cooler, depend-
ing on location and altered monsoonal
wind patterns in the Indian Ocean. Fortu-
itously for the present proposal, the ice
age simulations19 show that February west-
erlies on the African coast and along the
Indian Ocean equator were enhanced,
reaching wind velocities double what they
attain today. At the predicted Pleistocene
wind speeds of 10 to 25 knots, even a slug-
Iconography in Bradshaw rock art Pettigrew
© 2011 The Author Clinical and Experimental Optometry 94.5 September 2011
Clinical and Experimental Optometry © 2011 Optometrists Association Australia 409
gish raft-like fibre boat might approach
four knots, particularly if it had a wind-
catching profile, with a prow three to four
metres high and a 1.5 metre beam like
that depicted in the Bradshaw rock art. At
four knots, the 6,000-mile journey from
East Africa to NW Australia would take
approximately two months, which should
have been attainable if there was sufficient
rain to provide fresh water. The chances of
reaching Australian landfall would obvi-
ously be increased if there were multiple
boats, something it is impossible to
It is a tenuous exercise to attempt to
reconstruct the possible impact on an
ancient culture of a catastrophe, such as a
super-volcano eruption. In contrast, this
would clearly be an external influence that
helps remove the circularity of inferences
about the meaning of cultural icons. In
the present case, references to boabs in
Bradshaw art are recognised for the first
time as a direct result of considering these
trees in the broader context of the Toba
event. These references are not rare in
Tassel Bradshaw art but might not have
been recognised in the absence of the con-
textual cues that have been provided by
considering the possible impacts of this
well-defined, if remote, external event.
Toba catastrophe
Physical science gives us a precise date and
magnitude for the Toba super-volcano19
but there is presently no known icon that
might enable the direct recognition of this
event in rock art. Instead, we must resort
to indirect inferences.
The Toba eruption, 74,000 years ago,
puts the discussion in the right time frame
for the first human migrations to Australia
from Africa, particularly if we allow for the
extra delays and disruption to migration
produced by the widespread aftermath of
the volcano itself (Figure 8). At the time of
the eruption, Africa was populated by
Stone Age hunter-gatherers, probably
ancestors of the San peoples, well before
herdsmen appeared. Toba’s gigantic ash
Figure 7. Depictions of boats in Bradshaw rock art: (A) Small boat; the high prow might
be ceremonial, or perhaps reflect use in open ocean. (B) A drawing by Grahame Walsh of
a large boat depiction that was partly obscured by flow-stone overlay and did not photo-
graph well. The posterior end of the depiction was sufficiently free of the overlay that
horizontal striations could be discerned, possibly indicating a fibre construction (ála
Heyerdahl). Twenty occupants can be counted in the boat, which has a high prow that
suggests ocean-going capability.
Iconography in Bradshaw rock art Pettigrew
Clinical and Experimental Optometry 94.5 September 2011 © 2011 The Author
410 Clinical and Experimental Optometry © 2011 Optometrists Association Australia
cloud spread west from its origin in
Sumatra, atypical for a volcanic plume
because its huge mass, so close to the
equator, was subject to Coriolis forces.20
Plumes below this mass threshold are
subject to stratospheric winds rather than
Coriolis forces, which tend to disperse
and drive such smaller volcanic eruptions
roughly eastwards. Therefore, the ash
cloud was right in the migratory path of
humans from Africa to the Indies, with
significant ash coverage in Northern
Africa, the Middle East and India. In
India, the ash covered the sub-continent,
where it was at least three metres thick.
Dating studies of human stone tools found
above and below the ash layer have shown
that the layer immediately below the ash
has an age of 74,000 years, as expected,
but the tools resting just above the ash
were only 55,000 years old, indicating that
it took 19,000 years before the area was
recolonised after the eruption.21 The ear-
liest evidence of human habitation found
so far in Australia is 60,000 years old,22 very
much in keeping with a migration that
started close to the time of the Toba event
but was somewhat delayed by post-Toba
disruptions. This delay might have been
10 or more millennia as the migrants
passed through the Indies, just as recolo-
nisation was delayed until after vegetation
and game returned to ash-covered India.
Because the size of the Toba ejecta is
known from the size of its crater in
Sumatra, an estimate can be made of the
amount of sulphur released from the
ejecta to yield the likely magnitude and
duration of the sulphate cloud. Different
studies give somewhat different results
according to the size of the modelled sul-
phate particles, which settle faster when
larger, but all agree that the sun would
have been completely blacked out for
years by the sulphate cloud.23,24 Some
argue that Toba must have caused mass
extinction of humans, on the basis of the
reduced genetic variance now seen in the
descendants of the migrants who left
Africa compared with those who stayed
behind.25 Others are sceptical that there
were any major effects of Toba on the
human population.26 In response to the
sceptics, it is difficult to argue that years of
complete darkness would have had no
effect on hunter-gatherer bands, whose
game and plant food were dependent
on photosynthesis. Of course, the co-
operativeness and ingenuity of humans
would have lessened Toba’s impact. Also
important would have been local mitigat-
ing factors, such as the baobab forests, in
which the Sandawe lived and which pro-
vided the protein-lipid-rich seeds from
their fruit, which could be kept for years
and perhaps enabled defeat of the post-
Toba famine. Seafood harvested without
natural light might also have saved some
bands from the famine, although we do
not know whether the marine food chain
would have survived years of darkness
unscathed. Therefore, Toba’s effects
would have been highly idiosyncratic
and dependent on local conditions, but it
seems reasonable to expect some evidence
of its negative impact on hunter-gatherers,
even when they escaped the worst climatic
effects because they lived south of the ash
cloud and north of the bitter cold.
The baobab tree: a Stone Age
shopping mall
The Australian baobab tree, or boab,
Adansonia gregorii, is an unmistakable
member of the genus, the other members
of which are all located far away in Africa
and Madagascar. How did it make the
6,000 mile journey? A popular hypothesis
explains this in terms of continental drift
but Australia and Africa have not been
close for 100 million years, while the
genetics show that the African and Austra-
lian baobabs are almost identical, having
separated less than 100,000 years ago.27 An
exact figure is currently being sought
using the very large database necessary to
Attenuation (log 10)
01234 56
Years post eruption
Toba sulphate cloud
Dark night
Figure 8. Reconstruction of the catastrophic sulphate cloud
of the Toba megavolcano, replotted from Robock et al.,23 who
calculated the volume of ejecta from the Toba crater lake,
which is still extant, and the amount of sulphur from repre-
sentative rock in other volcanic eruptions. The darkness was
worldwide but may have been less than shown in some loca-
tions, such as the poles. Most hunting would have been
severely impacted by this level of darkness, but foraging for
seafood and for baobab fruit could have continued with torch-
light. This spike of five years of total darkness is known to
have been magnified to tens of thousands of years in India,
where metres of ash added further disruption to the darkness.
Iconography in Bradshaw rock art Pettigrew
© 2011 The Author Clinical and Experimental Optometry 94.5 September 2011
Clinical and Experimental Optometry © 2011 Optometrists Association Australia 411
study plant genes, which are notoriously
‘slow’ compared with mammal genes. The
timing of the African–Australian baobab
separation is compatible with the timing
of human migration out of Africa, which is
also uncertain, but likewise is less than
100,000 years.
The geographic distribution of boabs is
almost exactly the same as the distribution
of Bradshaw paintings, if we make allow-
ances for apparently recent eastward
extensions on the Victoria River and for
the ‘holes’ in the distribution of this
extremely frost-sensitive tree on the Kim-
berley plateau where there are both Brad-
shaws and occasional frosts.1,28 This is a
very narrow distribution compared with
the much larger stretch of the NW Austra-
lian coastline, where boabs could readily
grow. For this reason, it would seem very
unlikely that baobab pods floating in from
Africa would choose this narrow piece of
coastline, in this narrow time frame
(baobabs had been around for more than
a million years), when this was also the
time and place of the Bradshaw culture.
We know that boabs were an important
part of the Bradshaw culture because
Mushroom head icon
Mojo armpit drawstring bag
Affinity with small mammals
Praying mantis worship
Baobab references in rock art
Also in other San peoples
‘Peppercorn’ curly hair
Small stature
Exquisite delineation of fauna in art
Table 1. Unusual Sandawe–Bradshaw
Type of reference to baobab Number of exemplars Source
Boab frieze >100 Baobab site, DRNP
Leafless tree plus fruit (dry season boab)
Leafless tree and fruit ~80 Baobab site, DRNP
Roughly drawn naked tree with fruit ~80 Baobab site, DRNP
Fruit on leafy tree (wet season boab)
Boab leaves fruit 5 Bichrome rock, DRNP
Leaves and fruit 9 Bichrome rock, DRNP
Suspended ‘ceremonial’ fruit
Double decoration 2 Plates 21, 48 Walsh1
Single decoration 1 Plate 47 Walsh1
Single decoration 1 Walsh1
No decoration 1 Boab Bay, Faraway Bay
No decoration 5 Bradshaw Alley, DRNP
Striated halo 1 Walsh1
Fusion-transformation of limb to pod
Pod from hand 12 Plates 12, 17, 26 Walsh;1Boab Bay
Pod from foot 2 Plate 20 Walsh1
Boab garland 2 Bradshaw Alley, DRNP
Tree headdresses and dendrianthropes
Branching tree headdress 5 Boab Bay, Faraway Bay
Parallel fibre headdress 3 Lost City; Plate 11 of Walsh1
Tassel pom pom headdress 4 DRNP, Theda, Plates 27, 32, 36, 371
Total boab references ~300
Total paintings examined 104
Total paintings with boab references 54
Total Tassel Bradshaws with boab references 49
Total Sash Bradshaws with boab references 0
DRNP: Drysdale River National Park
Table 2. References to baobabs in Bradshaw rock art
Iconography in Bradshaw rock art Pettigrew
Clinical and Experimental Optometry 94.5 September 2011 © 2011 The Author
412 Clinical and Experimental Optometry © 2011 Optometrists Association Australia
there are frequent, reverential or ritual,
references to boabs in their art (as
detailed and illustrated below). There are
depictions of the tree itself, either heavily
laden with fruit (‘dry season’ aspect) or
with leaves and fewer fruit (‘wet season’).
More frequent are depictions of the pod
or nut, which is an important food source,
both because its pulp and seeds are nutri-
tious but because they are very long
lasting, keeping for years if kept dry.
Underlining the significance of boab pods
to the culture are depictions of transfor-
mations that are likely to have been the
result of a hallucinogenic trance, where
the forelimb of a human figure has been
transformed into a leafy boab branch
bearing a pod. Lewis-Williams11 has shown
how this kind of transformation is more
likely to involve a highly significant object
in the culture, such as the eland, a large
antelope, which was the single most
important food source for the San. The
transformation can be regarded as reveal-
ing what was on the mind of the shaman at
the time. The boab-arm transformation
suggests that shamans, with the role of
advising and guiding the culture, had
placed boabs in a place of importance.
Baobabs have extraordinary utility. The
list of uses that I keep continues to grow,
having reached 39 so far. Apart from the
variety of foods available from the edible
leaves, from pulp around the seeds and
from the seeds themselves, which are high
in fat and protein, baobabs yield a variety of
drugs, including an antidote for the arrow
poison used by the San, in addition to
glue, dye, fibre, oil, soap, starter/curdler,
shelter, containers, bee hives, et cetera.
The pod’s longevity should also be noted,
yielding unspoiled seed after a year on the
tree and further years in storage, a key
property that would enable survival in the
years of darkness of the post-Toba famine.
Many of these uses have been lost with the
advent of ‘corner stores’ all over Africa but
it is not too much of an exaggeration to call
the baobab the ‘Stone Age shopping mall’.
It would certainly have been chosen to take
on a long voyage like the one that I am
suggesting for the likely Sandawe ancestors
of the Bradshaw culture.
In this way, another example presents
itself for the task of breaking the circular-
ity inherent in studies of an extinct
culture, where the only available informa-
tion is rock art. Baobab trees are instantly
recognisable in both Australian and
African environments. They also occur in
rock art in both places. I am not aware of
any examples of transformations of the
human body into baobabs in Sandawe
rock art (or any other San art), like those
I have described in Bradshaw rock art, but
it is also true that references to baobabs in
Bradshaw art, including the transforma-
tions, are limited to early Tassel forms and
are not seen at all in later art (from Sash
forms onwards; Table 1). My interpreta-
tion of these differences hinges on the
relative importance of baobabs at different
times and in different cultures. If there
were abundant sources of other food, the
shamans might not have had the baobab
‘on their minds’ so much. Alternatively, in
the post-Toba famine, with the reduction
of foods that were directly or indirectly
dependent upon photosynthesis, the lon-
gevity of the baobab tree and its pod might
have played a crucial role in human sur-
vival through the years of darkness. This
might have engendered a reverential or
ritual attitude to this tree. After arrival in
NW Australia during the Pleistocene,
when there was an enormous fertile flood
plain, which is now inundated, that was
many times the area of the present Kim-
berley itself, the life-saving role played by
the baobab in the post-Toba famine and
the voyage might over thousands of
years have been gradually balanced in
the shamans’ minds by the abundant
resources of the new environment.
The collected examples of baobab ref-
erences in Bradshaw art are set out in
Table 2.
Baobab fruit (pods or nuts) are easy to
recognise in depictions as slightly asym-
metrical, variable in shape, often acumi-
nate at one end and ovoidal (Figure 9).
The only other natural object in the Kim-
Figure 9. Baobab frieze. A repetitive pattern of baobab pods and branches that was part
of a much larger panel, now deteriorated, onto which was later painted the baobab trees
shown in Figures 10A and 10B.
Iconography in Bradshaw rock art Pettigrew
© 2011 The Author Clinical and Experimental Optometry 94.5 September 2011
Clinical and Experimental Optometry © 2011 Optometrists Association Australia 413
berley that is even vaguely similar is the
emu egg, the ovoid of which has a differ-
ent, fatter, more symmetrical and much
less variable outline without an acuminate
An unusual depiction of baobab fruit
forms a repeated pattern (Figure 8), with
attached branches, that covers, or at least
once covered before deterioration, a large
area of the same rock wall on which are
overpainted exquisite baobab trees loaded
with pods (Figure 10). The term ‘frieze’
seems appropriate to describe this large,
regular decorative panel, in keeping with
the extensive decorative panels that adorn
ancient Greek structures, rather than ‘tap-
estry’ or ‘mosaic’, which might also apply
to repetitive artistic creations.
Depictions of four different baobab trees
can be recognised in Bradshaw art by the
characteristic fruit. Two are depicted in
the ‘dry season’ phase (Figure 10) when
there are no leaves and abundant fruit.
Two further trees are depicted in the ‘wet
season’ phase when leaves are abundant
and most fruit has fallen.
Although such depictions do not feature
in the publications that detail Sandawe
rock art,29 my personal examination of the
Kolo site revealed unmistakable baobabs,
in keeping with the importance of the tree
for this culture and its prevalence in
that area (Figures 11 and 12). Adjacent to
the baobab depiction was a figure with
a parallel-fibre headdress. These are
common throughout the Kolo site and
tend to be discounted on any specific basis
because many tribes, like the Masai, might
adopt a similar hairstyle. In this case, a
particular point can be made because of a
deep similarity between the depiction of
the baobab and the depiction of the
nearby parallel-fibre headdress. The simi-
larity arises because the baobab is depicted
a little figuratively, with parallel branches
that are curved to follow the curved crown
of the tree (Figure 11a). Because the
nearest painted image to the baobab is a
human figure with a parallel-fibre head-
dress, and because the parallel fibres are
similar in both cases, it is hard to avoid the
conclusion that the artist intended the
Similar parallel-fibre headdresses occur
in Bradshaw art (Figure 12). It seems rea-
sonable to assume these also represent a
reference to the baobab.
Walsh1recognised that these depictions
were united by the same object at their
core, despite the variations in the decora-
tions and the uniform reverentially sus-
pended treatment of each. He called them
Ceremonial Oval Objects, in which the oval
resembles a boab pod (nut or fruit) more
than any other natural object, including
the fatter, less variable outline of an emu
egg (Figure 11). Walsh did not venture any
opinion about their identity, which is
obvious to me because of the many strands
of the boab’s wider context that might rec-
ommend the approach taken here.
Tree headdresses and
Headdresses are ubiquitous in depictions
from the Tassel and Sash styles. Some of
Figure 10. (A) and (B). Two depictions of baobab trees, side by side on the same rock
wall. They were painted on top of the repetitive pattern of baobab fruit depicted in
Figure 9 (the baobab frieze). Both of these trees depict ‘dry season’ conditions, when the
leaves have been shed to reveal a maximal number of pods. The shape of the pods is
diagnostic. (C). A ‘wet season’ baobab showing the digitate (4 to 5 leaflets) leaves that
characterise this species and the small number of pods, which mostly would have been
shed around the time of flowering and leafing at the start of the wet (contours traced in
black). 10 (D) and (E). Transformation from forelimb to baobab branch, complete with
a pod to clinch the diagnosis. In African rock art, transformations are usually with
animals. Transformations involving baobab trees indicate that this tree may have been
very important to the culture and was likely to have been a key subject of trance
visualisations, just as the eland was to the Khoisan.
Iconography in Bradshaw rock art Pettigrew
Clinical and Experimental Optometry 94.5 September 2011 © 2011 The Author
414 Clinical and Experimental Optometry © 2011 Optometrists Association Australia
these headdresses are unmistakeable
trees, such as the one shown in Figure 13.
This example is taken from a site where
there were four other figures with the
same style of branched headdress. These
obvious trees do not bear a Linnaean label
of their species but we are entitled to
assume that they represent the baobab,
because of the context that has been
woven here for this tree and because there
is no conceivable tree from NW Australia
with greater utility and significance to a
Stone Age culture. If visualisation of one’s
head being replaced by a mushroom is
possible, what about a head replaced by
the most significant species of tree? Fig-
ure 13 shows what might be an example
of this phenomenon, a dendrianthrope,
which refers to a tree–human hybrid, just
as therianthrope refers to a mammal–
human hybrid. The branching in this
depiction is so elaborate that the head, if it
is present at all, is not visible and we might
interpret this depiction as a dendrian-
thrope rather than the figure with a tree
headdress that first comes to mind.
Timing of baobab references
Walsh1was able to define a temporal
relationship between Tassel and Sash
Bradshaw styles by using superposition,
observing which style was painted over
which when they were both found
together. Although later students of Brad-
shaw art have found a degree of temporal
overlap, there seems to be general agree-
ment that the Tassel style preceded the
Sash style. In this regard, it is of great inter-
est that whenever one can attribute the
baobab reference to a particular style, it is
always the earlier Tassel style (Table 1). In
the case of the four depicted baobab trees,
there is no way to link them definitively to
a particular style, although the simple
depictions of human figures that are
nearby on the same wall might also be
linked tentatively to the Tassel period (J
Schmiechen, personal communication).
The disappearance of baobab refer-
ences at the transition from the Tassel to
the Sash epochs could indicate that the
perceived importance of baobabs waned
with time as the culture developed from
beginnings where baobabs (or their
Figure 11. 11a, Original art work for 11.1. Ceremonial baobab fruit, (called ‘ceremonial
oval objects by Walsh1) at either (11.2) or both ends (11.1, 11.3 and 11.4) or depicted with
a radiating halo of lines like the adjacent human figure (11.5) but there is a constant
underlying baobab pod shape. The depictions have been rotated from their original
orientation on the rock wall to facilitate comparison. The ovoid shape varies somewhat,
just as in life, and is distinctly different in outline (for example, more parallel sides) from
the only other natural ovoid object depiction with which it might be confused, such as the
emu egg, which is much less variable in shape and has a fatter ovoid. The baobab pods
are always suspended in space, rather than being held. Combined with the decoration and
the halo, this supports a ceremonial or reverential attitude to the most nutritious and
long-lived part of the baobab tree, in keeping with the present thesis that it played a
crucial role in survival post-Toba.
Figure 12. Parallel-fibre headdresses (A and C) and figurative baobab depiction (B): B
and C are derived from Sadawe rock art at Kolo, Tanzania, while A is derived from
Bradshaw rock art in the Eastern Kimberley. The baobab is unmistakable because of its
very thick trunk. The parallel branches show some artistic licence, which is common in
this art, particularly for depictions of Euphorbia candelabra. Curved parallel fibre head-
dresses are common in both cultures and may have been inspired by this figurative
baobab because it was immediately adjacent to depictions of the Sandawe headdress.
Iconography in Bradshaw rock art Pettigrew
© 2011 The Author Clinical and Experimental Optometry 94.5 September 2011
Clinical and Experimental Optometry © 2011 Optometrists Association Australia 415
memory) were more important, consistent
with the scenario of a post-Toba and
baobab-enabled start.
Contra-opinion on trance
Walsh1rejected the idea that the Brad-
shaw images, with which he had such
detailed familiarity, might represent
trance visualisations álaLewis-Williams.11
His expressed opinion was based on a
consideration of the grid of dots image,
but not on any of the many other halluci-
natory visualisations listed above. The
specific image with dots that was chosen
by Walsh was not actually an example
of the hallucinogenic type of grid and
might explain his scepticism about this
approach. The image he chose, from
Bradshaw Alley in Drysdale National Park,
has well-separated, linear arrays of dots
rather than a regularly spaced array. In
this case chosen by Walsh, the rows of dots
probably represent a previous pattern of
lines that were punctuated with coloured
ochre (like a row of beads) and where the
interrupted ochre has weathered away. It
is instructive to compare Walsh’s chosen
example with the two examples of the grid
of dots illustrated here that conform more
to expectations about this phenomenon,
if it were based on trance (Figures 3 and
4). Notice that the more likely candidates
have larger diameter dots in relation to
the dots on the human figure (for
example, in the hair) and that they
occupy a uniform grid, with no hint of the
linear arrangement that is obvious in
Walsh’s choice, and there is no evidence
of order that might betray an earlier
pattern before the ochre wore off. If
Walsh considered different examples of
possible trance visualisation apart from
the grid, he has not set them out in any of
his books. Based on the example he
described, Walsh9appears to be wrong on
this issue, because there is abundant evi-
dence of different depictions of trance
visualisations in Bradshaw art.
Bradshaw shamanism in
other studies
Observations in rock art of the ubiquitous
practice of shamanism are not new.
Michaelson and colleagues30 inferred sha-
manism from completely different Brad-
shaw icons to those put forward here, such
as ‘ecstatic postures’, bifid antenna-like
headdresses and depictions of eucalyptus
leaves, which they suggest are mild psyche-
delics. These arguments are a little
tenuous, like many made here, and illus-
trate the inherent circularity, if there is no
external anchor. In contrast, Michaelson
and colleagues30 seem to be correct about
shamanism in Bradshaw culture, if one
adds the extra information put forward
here. They appear to have learned a
gestalt for the recognition of shamanism
in Bradshaw art without specifically iden-
tifying any of the icons on the list in this
Need for dating
The link between baobab references and
the Toba event would obviously be much
improved with more precise dating of the
depictions, which we predict will have an
age around 70,000 years, close to the time
of the Toba event, with the Tassel Brad-
shaws baobab references earlier, by some
more precise amount, than the Sash Brad-
shaws, where we can find no references. A
new approach to dating of individual
paintings uses microorganisms that have
replaced the original paint.8This discov-
ery helps explain how paintings can look
young but be very old (infinite replenish-
ment of the microorganisms is possible)
and why radiocarbon and similar methods
Figure 13. Tree-on-head depictions: Although we do not have the diagnostic outline of
baobab fruit in these depictions, we are entitled to assume that the depictions represent
baobabs. Many details of the baobab context have been established for the Bradshaw
culture and this tree, of all the trees in the forests of north west ice-age Australia, would
be the number one priority for a hunter-gatherer on account of its extreme utility (more
than 40 uses for foods, pharmaceuticals, fibre, dye, glue et cetera). These depictions
were found on the eastern edge of the Kimberley escarpment, close to the Timor Sea.
Depiction (A) was found alongside four other depictions of human figures with similar
branched headdresses. The branching pattern in depiction (C) is so elaborate that it
completely obscures the head, if indeed a head is present at all. It is possible that this is
a dendrianthrope, part-human part-tree, where the head has been replaced by a tree, just
as the head was replaced by a mushroom in the first example in this paper.
Iconography in Bradshaw rock art Pettigrew
Clinical and Experimental Optometry 94.5 September 2011 © 2011 The Author
416 Clinical and Experimental Optometry © 2011 Optometrists Association Australia
give anomalously young dates7(the organ-
isms in the painting are alive and there-
fore have modern C14 levels). The new
observations on biofilms in Bradshaw
paintings might constrain experiments
with paint composition in a way that helps
reveal some details about the original art-
ists,8in addition to the possibility of pro-
viding a date for each painting based on
the phylogeny of its microorganisms.
There are hundreds more icons in Brad-
shaw art to be decoded in addition to the
beginnings presented here. Two promi-
nent examples include a three-point waist
accoutrement seen in both Tassel and
Sash Bradshaws and the double-wing
accoutrement that adorns the headdress
of Sash Bradshaws only. Although there
have been suggestions of a practical role,
three-point tassels and sashes seem to have
a ceremonial role, as well as having a par-
allel in Saharan rock art and in the related
jewellery of the Tuareg, for whom the
three points represent the Southern Cross
constellation (R Weiler and A Weiler,
personal communication). This Saharan
(Tassili n’Ajer) three-point connection
could be tested further. Walsh1has
pointed out that the temporal progression
of icons in Bradshaw art is the reverse of
what normally occurs in cultural evolu-
tion, because complex, sophisticated
forms come first and there is a later pro-
gression to simpler ones. It is as if the
culture has sprung forth fully formed.
The succession of baobab references,
described here for the first time, conforms
to this rule and has even provided a pos-
sible explanation. There are unusual
exceptions to the rule, such as the timing
of the beautiful, feathered, double-wing
accoutrement, which occurs only later, in
a temporal relationship that is comple-
mentary to the baobab references. Further
investigation of this transition from Tassel
to Sash epochs could help illuminate the
meaning of many more Bradshaw icons, as
could better information on the age of
individual paintings.
Generous sharing of information about
rock art sites was provided by Cecilia
Myers, Steve McIntosh, Anscar MacPhee,
Lee Scott-Virtue and Joc Schmiechen.
James Sokoll provided valuable back-
ground information on Bradshaw art and
on his late friend and colleague, Grahame
Walsh. Visitation of art sites in the Wanjina
Wunggurr Wilinggi area was under a
permit from the Kalumburu Aboriginal
1. Walsh GL. Bradshaw Art of the Kimberley.
Toowong: Takarakka Nowan Kas Publications,
2. Roberts R, Walsh GL, Murray A, Olley R, Jones R,
Morwood MJ, Tuniz C et al. Luminescence dating
of rock art and past environments using mud-wasp
nests in northern Australia. Nature 1997; 387: 173–
3. Yoshida H, Roberts RG, Olley JM. Progress towards
single-grain optical dating of fossil mud-wasp nests
and associated rock art in northern Australia. Quat
Sci Rev 2003; 22: 1273–1278.
4. Akerman K, Willing T. An ancient rock painting of
a marsupial lion, Thylacoleo carnifex, from the Kim-
berley, Western Australia. Antiquity 2009; 18: 319.
5. Roberts RG, Brook BW. And then there were
none? Science 2010; 327: 420–422.
6. Vickers C, Pettigrew JD. Origins of the Australian
Boab (Adansonia gregorii). 2010. Available from:
7. Watchman A. Dating the Kimberley rock paint-
ings. In: Kenneally KF, Lewis MR, Donaldson M,
Clement C, eds. Aboriginal Rock Art of the Kim-
berley. Occasional paper No. 1. Perth, Western
Australia: Kimberley Society, 1997. p 39–46.
8. Pettigrew JD, Callistemon C, Weiler A, Gorbushina
A, Krumbein W, Weiler R. Living Pigments in Aus-
tralian Bradshaw Rock Art. Antiquity 2010 84: 326.
Available from:
9. Walsh GL. Bradshaws: Ancient rock paintings of
North-West Australia. Takarakka rock art research
centre. Carouge-Geneva, Switzerland, 1994.
10. Carter OL, Callistemon C, Presti DE, Liu GB,
Ungerer Y, Pettigrew JD. Meditation alters percep-
tual rivalry in Tibetan Buddhist monks. Curr Biol
2005; 15: 412–413.
11. Lewis-Williams DJ. The Mind In The Cave: Con-
sciousness And The Origins Of Art. London:
Thames & Hudson. 2002.
12. van Stight S. History. In: Church of the Sacred
Mushroom. 2010. Available from: http://
13. Cavallo J. Food of the Gods. In: The Bushmen:
Rock Art Conservation Centre. 2009. Available
14. Carter OL, Burr DC, Pettigrew JD, Wallis GM,
Hasler F, Vollenweider FX. Using psilocybin to
investigate the relationship between attention,
working memory and the serotonin1A and 2A
receptors. J Cogn Neurosci 2005; 17: 1497–1508.
15. Bednarik R. Iconography. 2002. Available from:
16. Webb S. Further research of the Willandra Lakes
fossil footprint site, southeastern Australia. J Hum
Evol 2007; 52: 711–715.
17. Jenkins OB. People profile. In: The Sandawe of
Tanzania. The Virtual Research Centre. 2008.
Available from:
18. Atlas of Pilot Charts for the Major Oceans of the
World: Indian Ocean Pilot Charts—Pub. #109;
September 2001. Available from: http://www.
19. Rampino MR, Self S. ‘Climate–volcanism reed-
back and the Toba eruption of ~74,000 years ago’.
Quat Res 1993; 40: 269–280.
20. Baines PG, Sparks RSJ. Dynamics of giant volcanic
ash clouds from supervolcanic eruptions. Geophys
Res Lett 2005; 32: L24808.
21. Balter M. Of two minds about Toba’s impact.
Science 2010; 327: 1187–1188.
22. Roberts RG, Jones R, Spooner BN, Head MJ,
Murray AS, Smith MA. The human colonisation of
Australia: optical dates of 53,000 and 60,000 years
bracket human arrival at Deaf Adder Gorge,
Northern Territory. Quat Geochronol (Quat Sci Rev)
1994; 13: 575–583.
23. Robock A, Ammann CM, Oman L, Shindell D,
Levis S, Stenchikov G. Did the Toba volcanic erup-
tion of ~74 ka B.P. produce widespread glaciation?
J Geophys Res 2009; 114, D10107, doi:10.1029/
24. Timmreck C, Graf H-F, Lorenz SJ, Niemeier U,
Zanchettin D, Matei D, Jungclaus JH et al. Aerosol
size confines climate response to volcanic super-
eruptions. Geophys Res Lett 2010; 37: L24705.
25. Atkinson QA. Phonemic diversity supports a serial
founder effect model of language expansion from
Africa. Science 2011; 332: 346–349.
26. Hawks J. At last, the death of the Toba bottleneck.
Available from:
27. Baum DA, Small RL, Wendel JF. Biogeography
and floral evolution of baobabs (Adansonia, Bom-
bacaceae) as inferred from multiple data sets. Syst
Biol 1998; 47:181–207.
28. Bowman DMJS. Observations on the demography
of the Australian boab (Adansonia gibbosa)inthe
North-west of the Northern Territory, Australia.
Aust J Bot 1997; 45: 893–904.
29. Leakey M. Africa’s vanishing art. Garden City, NY:
Doubleday & Co., 1983.
30. Michaelsen P, Ebersole TW, Smith NW, Biro P.
Australian ice age rock art may depict Earth’s
oldest recordings of Shamanistic rituals. Mankind
Quart 2000; 14: 131–146.
Corresponding author:
Professor Jack Pettigrew
School of Biomedical Sciences and
Queensland Brain Institute
University of Queensland
Brisbane QLD 4072
Iconography in Bradshaw rock art Pettigrew
© 2011 The Author Clinical and Experimental Optometry 94.5 September 2011
Clinical and Experimental Optometry © 2011 Optometrists Association Australia 417
... For example, the oldest recorded art made by Neanderthals is believed to be approximately 65,000 years old, created on stalagmites in Cueva de Ardales, in southern Spain (Martí, 2021). The earliest evidence showing the intersection between bacteria and art dates back to around 46,000 to 70,000 years ago with the Australian Bradshaw rock art also referred to as the Gwion Gwion paintings ( Figure 1A), located on sandstones in the North-West Kimberly region of Western Australia (Pettigrew, 2011). ...
Full-text available
Living art made with bacteria is gaining global attention, spreading from laboratories into the public domain: from school STEAM (Science, Technology, Engineering, the Arts and Mathematics) events, to art galleries, museums, community labs, and ultimately to the studios of microbial artists. Bacterial art is a synthesis of science and art that can lead to developments in both fields. Through the 'universal language of art', many social and preconceived ideas - including abstract scientific concepts - can be challenged and brought to the public attention in a unique way. By using bacteria to create publicly accessible art pieces, the barriers between humans and microbes can be lessened and the artificial separation of the fields of science and art may be brought one step closer. Here, we document the history, impact, and current moment in the field of microbiologically-inspired art for the benefit of educators, students, and the interested public. We provide a comprehensive historical background and examples of ancient bacterial art from cave paintings to uses in modern synthetic biology, a simple protocol for conducting bacterial art in a safe and responsible manner, a discussion of the artificial separation of science and art, and the future implications of art made from living microbes.
... Psychedelics may be the oldest known psychoactive agents [6]. The earliest representation of psychedelics may be seen in the prehistoric rock art of Bradshaw in Australia and Sandawe rock art in Eastern Tanzania, where drawings of mushroom heads might have represented psilocybin use by shamans for religious rituals and mystical experiences [7]. Other similar rock arts of mushrooms depicting higher states of consciousness have been found in places such as Saharan Epi-Paleolithic paintings of the "Round Heads" phase, dated to 7000-5000, rock paintings of Fuente de Selva Pascal, Spain, dated to 6000-4000 BC, Bronze Age rock art of Scandinavia, England, and Southern France [8]. ...
Full-text available
Psychedelics might be the oldest psychoactive agents known used for inducing religious or mystical experiences. Their strong psychoactive effect was discovered accidentally in 1943 after the synthesis of Lysergic acid diethylamide (LSD) in 1937. These drugs became a mainstream area of research following the synthesis of LSD, however, several political and social factors led to their ban in 1966, after which research on psychedelics was limited. These drugs became a major topic of scientific and ethical debate in the 1990’s and the recent times have seen a ‘Psychedelic renaissance’ where the therapeutic value of psychedelics is being reconsidered. This article reports the historic perspective of psychedelics, pharmacologic action by 5-HT2A receptor agonism, psychological effects and compares the proposed therapeutic uses including uses in depression, PTSD, anxiety-related disorders, drug and alcohol addiction, neurodegenerative diseases and auto-immune diseases to potential harms including development of tolerance, hallucinogen persisting perception disorder and potential psychosis. An analysis of history, pharmacology, and comparison of benefits and harms lead to the conclusion that the potential therapeutic benefits significantly outweigh the potential harms thus further research and clinical trials need to be conducted across different countries and cultures for legal approval in clinical use.
... Psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine) is also one of the classical serotonergic psychedelics, producing a similar psychoactive effect to LSD and mescaline. It has a long history of use dating back to 10,000 bce, with rock-etched murals of the psychedelic in northern Australia depicting mushroom iconography [14]. In 1959, the Swiss chemist Albert Hoffman isolated the active ingredient, psilocybin, from the Psilocybe mexicana mushroom [15]. ...
Full-text available
The use of psychedelics as medicines and for overall better brain health is potentially one of the most transformative developments given their immediate and long-lasting therapeutic effects across a plethora of neuropsychiatric disorders and, more recently, some neurodegenerative diseases. The US psychedelic drugs market is forecasted to grow by 16.3% by 2027 due to the increasing prevalence of treatment-resistant depression and mental health disorders. Decades-long restrictions, which date back to when psychedelics were declared controlled substances in 1970, have been lifted to allow researchers to publish on the therapeutic benefits of psychedelics. This review will feature the incredible depth of research underway revealing how psychedelics impact brain structure and function to treat mental health and other neurological disorders.
... Mushrooms have been used in diet and for medicinal purposes since prehistory and in all continents. 29,30 Theophrastus (circ. BC 300) was probably the earliest to notice the fungi. ...
Full-text available
Non-alcoholic fatty liver disease (NAFLD) is a most important cause of liver disease. Similar to other non-communicable diseases (NCD), such as obesity and type II diabetes mellitus, NAFLD can strongly affected by diet. Diet-related NCD and malnutrition are rising in all regions being a major cause of the global health, economic and environmental burdens. Mushrooms, important dietary components since the hunter-gathering communities, have increasingly gained momentum in biomedical research and therapeutics due to their interplay in metabolism traits. We emphasize here the beneficial effects of mushroom-enriched diets on the homeostasis of lipid and sugar metabolism, including their modulation, but also interfering with insulin metabolism, gut microbiota, inflammation, oxidative stress and autophagy. In this review, we describe the cellular and molecular mechanisms at the gut-liver axis and the liver-white adipose tissue (WAT) axis, that plausibly cause such positive modulation, and discuss the potential of mushroom-enriched diets to prevent or ameliorate NAFLD and related NCD, also within the shift needed toward healthy sustainable diets.
... Worldwide, different hallucinogens have been suggested as inspiring rock art making, such as mushrooms, Peyote, Datura, San Pedro cactus, Brunsvigia, and others (2,(28)(29)(30)(31)(32)(33)(34)(35). Datura is of particular focus in the North American West. ...
Full-text available
Significance Proponents of the altered states of consciousness (ASC) model have argued that hallucinogens have influenced the prehistoric making of images in caves and rock shelters. However, the lack of direct evidence for the consumption of hallucinogens at any global rock art site has undermined the ASC model. We present the first clear evidence for the ingestion of hallucinogens at a rock art site, in this case, from Pinwheel Cave, California. Quids in the cave ceiling are shown to be Datura wrightii , a Native Californian entheogen, indicating that, rather than illustrating visual phenomena caused by the Datura , the rock paintings instead likely represent the plant and its pollinator, calling into question long-held assumptions about rock art and the ASC model.
Hallucinogenic mushrooms have been used in religious and cultural ceremonies for centuries. Of late, psilocybin, the psychoactive compound in hallucinogenic mushrooms, has received increased public interest as a novel drug for treating mood and substance use disorders (SUDs). In addition, in recent years, some states in the United States have legalized psilocybin for medical and recreational use. Given this, clinicians need to understand the potential benefits and risks related to using psilocybin for therapeutic purposes so that they can accurately advise patients. This expert narrative review summarizes the scientific basis and clinical evidence on the safety and efficacy of psilocybin-assisted therapy for treating psychiatric disorders and SUDs. The results of this review are structured as a more extensive discussion about psilocybin’s history, putative mechanisms of action, and recent legislative changes to its legal status. There is modest evidence of psilocybin-assisted therapy for treating depression and anxiety disorders. In addition, early data suggest that psilocybin-assisted therapy may effectively reduce harmful drinking in patients with alcohol use disorders. The evidence further suggests psilocybin, when administered under supervision (psilocybin-assisted therapy), the side effects experienced are mild and transient. The occurrence of severe adverse events following psilocybin administration is uncommon. Still, a recent clinical trial found that individuals in the psilocybin arm had increased suicidal ideations and non-suicidal self-injurious behaviors. Given this, further investigation into the safety and efficacy of psilocybin-assisted therapy is warranted to determine which patient subgroups are most likely to benefit and which are most likely to experience adverse outcomes related to its use.
Full-text available
Found only in a restricted area of north-west Australia, the Australian boab ( Adansonia gregorii ) is recognisable by its massive, bottle-shaped trunk, and is an economically important species for Indigenous Australians, with the pith, seeds and young roots all eaten. Many of these trees are also culturally significant and are sometimes carved with images and symbols. The authors discuss the history of research into carved boabs in Australia, and present a recent survey to locate and record these trees in the remote Tanami Desert. Their results provide insight into the archaeological and anthropological significance of dendroglyphs in this region and add to a growing corpus of information on culturally modified trees globally.
Full-text available
Our hominin ancestors inevitably encountered and likely ingested psychedelic mushrooms throughout their evolutionary history. This assertion is supported by current understanding of: early hominins’ paleodiet and paleoecology; primate phylogeny of mycophagical and self-medicative behaviors; and the biogeography of psilocybincontaining fungi. These lines of evidence indicate mushrooms (including bioactive species) have been a relevant resource since the Pliocene, when hominins intensified exploitation of forest floor foods. Psilocybin and similar psychedelics that primarily target the serotonin 2A receptor subtype stimulate an active coping strategy response that may provide an enhanced capacity for adaptive changes through a flexible and associative mode of cognition. Such psychedelics also alter emotional processing, self-regulation, and social behavior, often having enduring effects on individual and group wellbeing and sociality. A homeostatic and drug instrumentalization perspective suggests that incidental inclusion of psychedelics in the diet of hominins, and their eventual addition to rituals and institutions of early humans could have conferred selective advantages. Hominin evolution occurred in an ever-changing, and at times quickly changing, environmental landscape and entailed advancement into a socio-cognitive niche, i.e., the development of a socially interdependent lifeway based on reasoning, cooperative communication, and social learning. In this context, psychedelics’ effects in enhancing sociality, imagination, eloquence, and suggestibility may have increased adaptability and fitness. We present interdisciplinary evidence for a model of psychedelic instrumentalization focused on four interrelated instrumentalization goals: management of psychological distress and treatment of health problems; enhanced social interaction and interpersonal relations; facilitation of collective ritual and religious activities; and enhanced group decision-making. The socio-cognitive niche was simultaneously a selection pressure and an adaptive response, and was partially constructed by hominins through their activities and their choices. Therefore, the evolutionary scenario put forward suggests that integration of psilocybin into ancient diet, communal practice, and proto-religious activity may have enhanced hominin response to the socio-cognitive niche, while also aiding in its creation. In particular, the interpersonal and prosocial effects of psilocybin may have mediated the expansion of social bonding mechanisms such as laughter, music, storytelling, and religion, imposing a systematic bias on the selective environment that favored selection for prosociality in our lineage.
Jack Pettigrew spent much of his time and energy over the last decade after his retirement exploring the mysterious Bradshaw figures which are part of the rock art found in the Kimberley region of Western Australia. This article is protected by copyright. All rights reserved.
Investigation of consciousness (experience, mind, awareness, subjectivity) has become an accepted endeavor in contemporary neuroscience. However, current work is largely limited to study of neural correlates of consciousness. While this is interesting and important, it may not be sufficient to carry us to a place of truly new insight regarding consciousness. I argue that one element of expanding a science of consciousness is appreciation of the interdependent co-creation or enfolding of mind and world. Addressing this interdependence is an aspect of the collaborative engagement of the traditions of Buddhism and science - a project that is exploring how complementary worldviews and analytic procedures might further the development of an expanded science of mind. In this essay, written for a collection honoring the life and work of Jack Pettigrew, I describe his connection to this project. This article is protected by copyright. All rights reserved.
Full-text available
The phylogeny of baobab trees was analyzed using four data sets: chloroplast DNA restriction sites, sequences of the chloroplast rpl 16 intron, sequences of the internal transcribed spacer ITS region of nuclear ribosomal DNA, and morphology. We sampled each of the eight species of Adansonia plus three outgroup taxa from tribe Adansonieae. These data were analyzed singly and in combination using parsimony. ITS and morphology provided the greatest resolution and were largely concordant. The two chloroplast data sets showed concordance with one another but showed significant conflict with ITS and morphology. A possible explanation for the conflict is genealogical discordance within the Malagasy Longitubae, perhaps due to introgression events. A maximum likelihood analysis of branching times shows that the dispersal between Africa and Australia occurred well after the fragmentation of Gondwana and therefore involved overwater dispersal. The phylogeny does not permit unambiguous reconstruction of floral evolution but suggests the plausible hypothesis that hawkmoth pollination was ancestral in Adansonia and that there were two parallel switches to pollination by mammals in the genus.
Full-text available
Bradshaw rock art, unique to the Kimberley, Northwestern Australia, depicts human-like figures characterized by extensive headdresses and elaborate body ornamentation. Numerous figures seem to float in space, as though in ecstatic behavior. Bradshaws, at least 17,500 years of age, may represent the world's oldest depictions of shamans and shamanistic rituals. Significantly, recent discoveries indicate some shamans may have been women. The worldwide distributional pattern of shamanism suggests it dispersed from a common source. Its possible representation in Bradshaw paintings gives important clues of the early spread of human behavioral patterns.
A general feedback between volcanism and climate at times of transition in the Quaternary climate record is suggested, exemplified by events accompanying the Toba eruption (∼74,000 yr ago), the largest known late Quaternary explosive volcanic eruption. The Toba paroxysm occurred during the δ18O stage 5a-4 transition, a period of rapid ice growth and falling global sea level, which may have been a factor in creating stresses that triggered the volcanic event. Toba is estimated to have produced between 1015 and 1016 g of fine ash and sulfur gases lofted in co-ignimbrite ash clouds to heights of at least 32 ± 5 km, which may have led to dense stratospheric dust and sulfuric acid aerosol clouds. These conditions could have created a brief, dramatic cooling or "volcanic winter," followed by estimated annual Northern Hemisphere surface-temperature decreases of ∼3° to 5°C caused by the longer-lived aerosols. Summer temperature decreases of ≥10°C at high northern latitudes, adjacent to regions already covered by snow and ice, might have increased snow cover and sea-ice extent, accelerating the global cooling already in progress. Evidence for such climate-volcanic feedback, following Milankovitch periodicities, is found at several climatic transitions.
Cited By (since 1996):6, Export Date: 26 November 2013, Source: Scopus
It has been suggested that the Toba volcanic eruption, approximately 74 ka B.P., was responsible for the extended cooling period and ice sheet advance immediately following it, but previous climate model simulations, using 100 times the amount of aerosols produced by the 1991 Mount Pinatubo eruption, have been unable to produce such a prolonged climate response. Here we conduct six additional climate model simulations with two different climate models, the National Center for Atmospheric Research Community Climate System Model 3.0 (CCSM3.0) and National Aeronautics and Space Administration Goddard Institute for Space Studies ModelE, in two different versions, to investigate additional mechanisms that may have enhanced and extended the forcing and response from such a large supervolcanic eruption. With CCSM3.0 we include a dynamic vegetation model to explicitly calculate the feedback of vegetation death on surface fluxes in response to the large initial reduction in transmitted light, precipitation, and temperature. With ModelE we explicitly calculate the effects of an eruption on stratospheric water vapor and model stratospheric chemistry feedbacks that might delay the conversion of SO2 into sulfate aerosols and prolong the lifetime and radiative forcing of the stratospheric aerosol cloud. To span the uncertainty in the amount of stratospheric injection of SO2, with CCSM3.0 we used 100 times the Pinatubo injection, and with ModelE we used 33, 100, 300, and 900 times the Pinatubo injection without interactive chemistry, and 300 times Pinatubo with interactive chemistry. Starting from a roughly present-day seasonal cycle of insolation, CO2 concentration, and vegetation, or with 6 ka B.P. conditions for CCSM3.0, none of the runs initiates glaciation. The CCSM3.0 run produced a maximum global cooling of 10 K and ModelE runs produced 8–17 K of cooling within the first years of the simulation, depending on the injection, but in all cases, the climate recovers over a few decades. Nevertheless, the “volcanic winter” following a supervolcano eruption of the size of Toba today would have devastating consequences for humanity and global ecosystems. These simulations support the theory that the Toba eruption indeed may have contributed to a genetic bottleneck.